Liquid thermal diffusion apparatus



Sept 2 1958 M. MIFINIK 2,850,167 Y LIQUID THERMAL DIFFUSION APPARATUS Filed May 14, 1956 INVENTOR. MELVIN M. FINK ATTORN' EY United States Patent LIQUID THERMAL DIFFUSION APPARATUS Melvin M. Fink, Cleveland, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio Application May 14, 1956, Serial No. 584,576

4 Claims. (Cl. 210--176) The present invention relates to lan improved liquid thermal diffusion apparatus. More particularly, this invention relates toa unitary tubular type thermal diffusion apparatus containing a plurality of discrete separation chambers.

Liquid thermal diffusion is a process by means yof which the components of a liquid mixture may be concentrated and separated. The process is carried out by subjecting a t-hin film of the liquid to be separated to a temperature gradient and the separation is accomplished by means of the resultant `thermal forces within the liquid. Y

Apparatus which may be employed in carrying out a liquid thermal diffusion operation has been described in U. S. Patent No. 2,541,069 to Jones et al. Figure 1 of that patent illustrates a typical tubular-type apparatus for carrying out the thermal diffusion operation. In such an apparatus, concentric tubes are lemployed to form a narrow annular space of uniform width which serves as the separation chamber. The width of the separation chamber is necessarily quite narrow, less than 0.15 inch and preferably 0.02 to 0.06 inch. Means are provided for feeding a liquid to the separation chamber and for withdrawing products therefrom. Separation of a liquid mixture is effected in such an apparatus by impressing a ternperature gradient across the liquid which is confined in the annular space between the concentric tubes and means are provided for this purpose.

Heretofore, if a number of different liquids were to be thermally diffused, it was necessary to employ a separate apparatus of the type described in the Jones et al. patent referred to above for each liquid to be separated. The sa-rne conditions obtained if it was desired to subject the products of the thermal diffusion process to further refinement by thermal diffusion. Accordingly, `one of the objects of this invention is to provide a tubular type thermal diffusion `apparatus in which a single pair of concentric tubes is employed to form a plurality of discrete separation chambers which may be simultaneously employed to elect the separation of different liquids. Such an apparatus has the advantage of requiring a minimum of piping and other connections which are employed to supply the heat transfer mediums to the apparatus since the means for impressing the temperature gradient across the various liquids to be separated are common to all of the separation chambers.

In view of the criticality of the width of the separation chamber in a thermal diffusion apparatus, it is important that the surfaces forming the separation chamber be maintained relatively free from obstructions or deposits. It is well known that certain materials will foul `the separation chamber under the high temperatures which they may be subjected to in the thermal Idiffusion process. Consequently, the time required to clean the apparatus becomes an important consideration in determining the economics of subjecting such materials to the thermal diffusion process. Accordingly, it is another object of this invention to provide a tubular type apparatus which may be readily narrow thermal diffusion separation chamber.

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2 disassembled to facilitate cleaning operations on the apparatus.

In brief, my invention comprises a pair of'concentric tubes which are spaced apart so as to form a uniformly Means Iare provided at certain predetermined spaced distances along the length of the concentric tubes to seal the annu' lar space between the tubes so as to form a number of discrete separation chambers therebetween. provided for feeding liquids to and withdrawing products from each of the discrete separation chambers. Means are also provided for impressing a temperature gradient across each Vof the discrete separation chambers, but such means are common to all of the separation chambers.

A better understanding of the apparatus of this invention may be had by reference to the attached patent drawing wherein similar figures denote similar parts throughout and Where:

Figure l is 'a cross-sectional side view; and

Figure 2 is a top view of the apparatus looking down` from the plane 2-2.

tube 11 so' as to provide a uniform' annular space .15 therebetween. The cylinder 10 and the tube 11 may be formed of any heat-transmitting solid such as glass or metal. The cylinder 10 is provided with a plurality of grooves 16 in its outer wall at spaced points along its length. The grooves occur at intervals along the length of the cylinder 10. The grooves 16 may be in pairs, 16 and 16a, as shown at the ltop and bottom of Figure l, or there may be a single groove 16b as shown in the upper part of Figure l, `or in sets of three, 16C, 16d and 16e, as shown at the bottom part of Figure l. The grooves are adapted to receive la sealing means such as a resilient O-ring gasket 17 which serves to seal Ithe annular space 15. The gasket may be of natural or silicone rubber or a plastic, for example. The arrangement of the cylinder 10 and the tube 11 is lalso shown in Figure 2. One or more set screws 18 may ,be provided in openings such as 19 in the jacketed tube 11 to assure a uniform spacing between the cylinder 10 and the tube 11. The conduit means 12 and 13 communicate with the interior 14 of the cylinder 10 whereby a heat transfer medium such as steam or water may be admitted to the interior 14.

The jacket 11a which surrounds tube 11 is provided to accommodate a similar heat transfer medium. The heat transfer medium enters and leaves jacket 11a by means of the conduits 20a and 2Gb.

Suitable provisions are made in the tube 11 and the tube jacket 11a for the en'try of conduits 21-32, inclusive, which communicate with the exterior of the apparatus and the separation chamber 1S. The conduits 21-32 communicate with the separation chamber, and may be opposite a groove, as shown at 16a, 16C and 16e, in the outer wall of cylinder 10. Accordingly, such grooves 16 function as liquid reservoirs. In this manner, a unita-ry apparatus is provided in which a plurality 'of discrete separation chambers are provided by means of the sealing means 17 which effectively divides the separation chamber 15 into a number of discrete sections.

In one method of employing the apparatus of this invention, a liquid to be separated could be admitted to the separation chamber 15 through the conduits 21 and 22. In such an operation, enriched products of the thermal diffusion process would be withdrawn through conduits 27 land 28. Another liquid similarly could be fed through conduits 23 and 24 and withdrawn from conduits 29 and 30. Alternatively, the enriched liquid from either conduits Z7 or 2S could be fed to conduits 23 and 24.

One of the principal advantages of my invention is that 'Patented Sept. 2, 1958-` Means are 3. the apparatus may be easily disassembled. In order to disassemble the apparatus of this invention, it is only necessary to loosen the set screws 18 and pull the cylinder 10 out of the tube 11. Since the sealing means 17 are resilient, they furnish no..obstruction to the removalof the cylinder 10 from the tube 11 and they are the only elements of this apparatus which contact both thecylinder 10 and tube 11, as can be seen from Figures 1 and 2 of the patent drawing.

Another advantage of my invention arises from the use of ring gaskets as the sealing means, since these gaskets, due to their resilient nature, will inherently serve also as spacing means and maintain the uniformity of the annular space 15. This feature of the apparatus eliminates the need for separate spacing means.

I claim:

1. A thermal diffusion apparatus comprising a first tubular member secured within a second tubular member so as to form a narrow uniform annular space between the said tubular members, means for sealing said annular space at a plurality of pointsl along the length of said tubular members so as to forma plurality of discrete separation chambers, means for impressing a temperature gradient upon said separation chambers, means for feeding liquids to and withdrawing products from said separation chambers.

2. The apparatus of claim 1 in which said sealing means are resilient O-ring gaskets.

3. The apparatus of claim 2 in which the resilient O-ring gaskets are sealed within grooves in said first tubular member.

4. A thermal diffusion apparatus comprising a first ytubular member secured within a second tubular member so as to form a narrow uniform annular space between said tubular members, said second tubular member having openings at intervals therein and a jacket surrounding the entire member and a plurality of conduits cornmunicating with said openings and the outside of said jacket whereby liquids may be introduced and withdrawn from said separation chambers, means for sealing said annular space at a plurality of points along the length of said tubular members comprising a plurality of recesses in the wall of said first tubular member having a resilient O-ring gasket disposedy therein whereby a plurality of discrete separation chambers are formed, means for impressing a temperature gradient upon said separation chambers and reservoir means comprising a recess in said first tubular member forming a groove therein disposed immediately adjacent to each of the ends of each separation chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,541,069 JOneS Feb. 13, 1951 2,648,199 Alderson Aug. 11, 1953 2,701,146 Warren Feb. 1, 1955 2,727,761 Elliott Dec. 20, 1955 

1. A THERMAL DIFFUSION APPARATUS COMPRISING A FIRST TUBULAR MEMBER SECURED WITHIN A SECOND TUBULAR MEMBER SO AS TO FORM A NARROW UNIFORM ANNULAR SPACE BETWEEN THE SAID TUBULAR MEMBERS, MEANS FOR SEALING SAID ANNULAR SPACE AT A PLURALITY OF POINTS ALONG THE LENGTH OF SAID TUBULAR MEMBERS SO AS TO FORM A PLURALITY OF DISCRETE SEPA- 